Personal cleansing products have traditionally been marketed in a variety of forms such as bar soaps, creams, lotions, and gels. These cleansing formulations have attempted to satisfy a number of criteria to be acceptable to consumers. In order to be acceptable to consumers, a product must exhibit good cleansing properties, must exhibit good lathering characteristics, must be mild to the skin and preferably should provide a moisturizing benefit to the skin. Ideal personal cleansers should gently cleanse the skin or hair, cause little or no irritation, and not leave the skin or hair overly dry after frequent use.
These traditional forms of personal cleansing products have the inherent problem of balancing cleansing efficacy against delivering a conditioning benefit. One solution to this problem is for the consumer to use separate cleansing and conditioning products. This is not always convenient or practical and many consumers would prefer to use a single product which can both cleanse and condition the skin or hair. However, in typical cleansing compositions, the conditioning ingredients are difficult to incorporate because many conditioners are incompatible with the surfactants, resulting in an undesirable non-homogenous mixture.
To obtain a stable homogeneous mixture of surfactants and conditioning agents, two-phase emulsions have been formulated. The oil based conditioning agents are dispersed in the oil phase and the surfactant cleansing system is dispersed in the water phase. This results in an aesthetically pleasing uniform emulsion mixture, but can result in poor deposition of conditioning ingredients, because the conditioners are emulsified and not necessarily efficiently released during cleansing.
Also, most traditional skin conditioning oils have the disadvantage of suppressing lather generation. It is known that the addition of an oil to a surfactant solution results in a increase in interfacial tension of the solution due to the fact that the surfactant molecules are tied up with the oil at the oil-water interface of the emulsion. The increased interfacial tension decreases the lathering and cleaning ability of the surfactant. Lather suppression is a problem because many consumers seek cleansing products that provide a rich, creamy, and generous lather.
One way to provide cleansing compositions which incorporate both insoluble conditioning components and water-soluble cleansing components without the disadvantages particularly associated with the emulsion form would be therefore, to develop a non-emulsified form of cleansing composition with insoluble conditioners and water-based cleansers.
Applicants have found that, surprisingly, personal cleansing products which contain both insoluble skin conditioning ingredients and a cleaning surfactant can be formulated without forming an emulsion. Since no emulsion is formed, the interfacial tension of the surfactant solution remains low and the lathering and cleansing benefits of the surfactant are maintained. Without being limited by theory it is believed that since the insoluble skin conditioning ingredients are dispersed in the composition, they are more efficiently deposited to the skin, providing conditioning benefits. Also, since the insoluble skin conditioning ingredients are dispersed in the composition without dramatically increasing the interfacial tension of the cleansing components, the cleansing and lathering benefits of the cleansing component are not negatively affected.
The present invention relates to non-emulsified personal cleansing compositions which consist of a lathering surfactant based cleansing component and an insoluble skin conditioning component which does not increase the interfacial tension of the cleansing component by more than 150%. The compositions provide improved cleansing and skin conditioning benefits over traditional oil-in-water emulsion cleansers.